1. Field of the Invention
The present invention generally relates to an inkjet printer. More specifically, the present invention generally relates to a capping device for a print head of an ink-jet printer, which tightly seals the print head during a driving stop state or a printing standby mode, and a method thereof.
2. Description of the Related Art
FIG. 1 is a partially-cut perspective view illustrating a conventional ink-jet printer and a conventional capping device for a print head employed therein.
As shown in FIG. 1, a conventional inkjet printer 100 includes an ink cartridge 120, a carriage 130, and a capping device 140.
The ink cartridge 120 contains ink therein, and forms an image on a printing paper by jetting the ink through a print head disposed at a side thereof during a printing operation of the inkjet printer 100.
The carriage 130 is movably disposed in a printer body 110 and supports at least one ink cartridge 120. During a printing mode of the inkjet printer 110, the carriage 130 moves back and forth in the printer body 110 so that the ink is jetted onto a section of the printing paper through the print head 125. If the inkjet printer 110 prints a unicolored image such as a black and white document, the carriage 130 supports only one ink cartridge 120. If the inkjet printer 100 prints a multicolored image, however, the carriage 130 supports plural ink cartridges 120, as shown in FIG. 1.
Typically, if the inkjet printer 110 is in a printing standby mode or a driving stop state, the carriage 130 moves out of a printing area P into a service area S at a side of the printer body 110 and waits in the service area S until the inkjet printer 100 is changed to the printing mode.
The capping device 140 for the print head 125 tightly seals the print head 125 when the carriage 130 is located in the service area S. By sealing the print head 125, the capping device 140 prevents the print head 125 from being contaminated by foreign substances and also prevents the residual ink of nozzles of the print head 125 from solidifying and closing the nozzles. The capping device 140 includes a housing 141 connected to the print body 110 and a head cap 142 that moves in a vertical direction in the housing 141. The head cap 142 substantially seals the print head 125 and is disposed on a supporting member 143. If the ink cartridge 120 moves into the service area S, the supporting member 143 is moved upward by a driving device 150, and the head cap 142 seals the print head 125 of the ink cartridge 120.
The configuration and operation of the capping device of the conventional print head 125 is disclosed in US Patent Application No. 2003/0090535, the entire contents of which are incorporated herein by reference.
In the capping device 140 of the conventional print head 125, the head cap 142 tightly seals the print head 125. Hence, if a temperature increases while the print head 125 is capped, a pressure between the head cap 142 and the print head 125 also increases thereby damaging the print head 125. As shown in FIG. 2, there is no through hole in the head cap 142, to allow air to flow. As a result, while the print head 125 is sealed by the head cap 142, if the temperature around the print head 125 rises, the air sealed between the head cap 142 and the print head 125 expands to increase the pressure. If the pressure between the head cap 142 and the print head 125 rises, the meniscus of the ink, which flows from the ink storage of the ink cartridge 120 to the nozzle of the print head 125 and stays therein, is destroyed and the ink flows backward. The back-flow of the ink hinders effective ink firing through the nozzle.